Sha Lu

Synergistic effects of terbinafine and itraconazole on clinical isolates of Fonsecaea monophora

Our objective was to develop new approaches to the chemotherapy of invasive infections caused by Fonsecaea monophora. The in vitro effects of a combination of terbinafine with itraconazole on 18 clinical isolates were evaluated using a checkerboard microdilution method. The mode of interaction between the two drugs on the 18 isolates was analyzed using fractional inhibitory concentration index (FICI) analysis. FICI analysis demonstrated that 12 (67%) were synergistic, 4 (22%) were additive, and 2 (11%) were indifferent, with no antagonism being observed. The minimal inhibitory concentrations (MICs) obtained with the terbinafine-itraconazole combination were within levels that can be achieved in plasma at clinically relevant doses. Our results indicate the terbinafine-itraconazole combination may be an effective therapy for Fonsecaea monophora infection, which should be tested in clinical setting with patients with this disease.

Chromoblastomycosis in Mainland China: A Systematic Review on Clinical Characteristics

Chromoblastomycosis is one of the most frequent chronic infections caused by melanized fungi. In order to evaluate the clinical characteristics of chromoblastomycosis in Mainland China, we performed an evidence-based review of published literature. PubMed and Chinese-language database of CNKI, VIP and Wanfang data during January 1990–August 2011 were searched. Epidemiology, clinical features, laboratory findings, therapy and prognosis were analyzed. Cladophialophora carrionii was the most common causative agent in the north of the Mainland China, and Fonsecaea monophora and F. pedrosoi were the most common agents in the southern part of the Mainland China. Infection commonly initiated after the etiologic agents gain entrance through puncture wounds and more common involved extremities of the males. Skin lesions were found in different sites, like the extremities, buttocks, trunk and face, and presented diversity morphology. There were about seven different clinical types found in Mainland China: plaque type, tumoral type, cicatricial type, verrucous type, pseudo-vacuole type, eczymatous type and mixed type of lesions. The success of treatment for chromoblastomycosis was related to the causative agent, the clinical form and severity of the lesions. Most of the patients could be treated successfully with the physical treatment, chemotherapy and/or combination therapy. The itraconazole, terbinafine or a combination of both were commonly medication for these mycosis patients. Physical methods were usually indicated to support chemotherapy with some severe forms and long-lasting cases. Photodynamic therapy has been extended from the oncological field to that of antimicrobial chemotherapy in these years. We applied it on some recalcitrant cases of chromoblastomycosis and found its good clinical response, and hopeful it could be a promising therapy in near future.

Cutaneous protothecosis: two new cases in China and literature review

Protothecosis is a rare infection caused by Prototheca spp., which are achlorophyllous algae found in trees, various aquatic sources such as lakes and rivers, sewage treatment plants, soil, and household garbage. They can infect both humans and animals. Human protothecosis is rare, and most cases are found in immunocompromised patients. In mainland China, only four cases caused by Prototheca spp. have been reported. In general, clinical manifestations of reported cases can be classified into three clinical forms: cutaneous (66%); olecranon bursitis (15%); and disseminated or systemic infections (19%). Currently, Prototheca zopfii, P. wickerhamii, P. stagnora, P. ulmea, and P. blaschkeae are classified to the genus. Among these, only the former two have been reported to cause infections in humans, with P. wickerhamii being most common. In this article, two cases of cutaneous protothecosis caused by P. wickerhamii will be presented. Both patients responded well to treatment with intravenous voriconazole (VRC), although one died later from other complications.

Role of extracellular signal-regulated kinases 1 and 2 and p38 mitogen-activated protein kinase pathways in regulating replication of Penicillium marneffei in human macrophages.

Penicillium marneffei (P. marneffei) is a human pathogen which persists in macrophages and threatens the immunocompromised patients. To elucidate the mechanisms involved, we investigated the role of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38 mitogen-activated protein kinase (p38) pathways in cytokine expression, phagosome-lysosome fusion and replication of P. marneffei in P. marneffei-infected human macrophages. Analysis of both ERK1/2 and p38 showed rapid phosphorylation in response to P. marneffei. Using specific inhibitors of p38 (SB203580) and MAP kinase kinase-1 (PD98059), we found that ERK1/2 and p38 were essential for P. marneffei-induced tumor necrosis factor-α production, whereas p38, but not that of ERK, was essential for IL-10 production. Furthermore, the presence of PD98059 always decreased phagosomal acidification and maturation and increased intracellular multiplication of P. marneffei, whereas the use of SB203580 always increased phagosomal acidification and maturation and decreased intracellular replication. These data suggest that a proper balance of between ERK1/2 and p38 may play an important role in controlling the replication of P. marneffei. Our findings further indicate a novel therapeutic avenue for treating P. marneffei by stimulating ERK1/2 or activating ERK1/2-dependent mechanisms.

Whole blood Nested PCR and Real-time PCR amplification of Talaromyces marneffei specific DNA for diagnosis.

Talaromyces marneffei is a dimorphic pathogenic fungus, which is a life-threatening invasive mycosis in the immunocompromised host. Prompt diagnosis of T. marneffei infection remains difficult although there has been progress in attempts to expedite the diagnosis of this infection. We previously demonstrated the value of nested polymerase chain reaction (PCR) to detect T. marneffei in paraffin embedded tissue samples with high sensitivity and specificity. In this study, this assay was used to detect the DNA of T. marneffei in whole blood samples. Real-time PCR assay was also evaluated to identify T. marneffei in the same samples. Twenty out of 30 whole blood samples (67%) collected from 23 patients were found positive by using the nested PCR assay, while 23/30 (77%) samples were found positive by using the real-time PCR assay. In order to express accurately the fungal loads, we used a normalized linearized plasmid as an internal control for real-time PCR. The assay results were correlated as the initial quantity (copies/μl) with fungal burden. These data indicate that combination of nested PCR and real-time PCR assay provides an attractive alternative for identification of T. marneffei DNA in whole blood samples of HIV-infected patients.

Isolation of Penicillium marneffei From Soil and Wild Rodents in Guangdong, SE China

Infection by Penicillium marneffei is an important emerging public health problem, especially among travelers and inhabitants in SE China and SE Asia infected with human immunodeficiency virus (HIV). In recent years, the number of patients with penicilliosis marneffei (PM) has increased rapidly in Guangdong province, SE China. However, the natural habitat and transmission mode of the etiologic agent remains unclear. In this study, wild rats (Microtus, focus Rattus and Rhizomys pruinosus) and soil samples were collected from rat burrows, populated and rural areas from November 2007 to December 2008 for fungus cultures. All isolates, suspected of being P. marneffei, were identified by gross and microscopic morphology and ITS analysis. Sixteen of 23 (about 70%) bamboo rats were P. marneffei positive, whereas none was recovered from hamsters, loirs or soil. This suggests that as of today the bamboo rat is the exclusive natural reservoir for P. marneffei. Definite evidence that rodents are a part of the infectious cycle is still lacking.

Pseudomembranous-like tinea of the scrotum : report of six cases

Six cases of tinea of the scrotum with atypical clinical features were observed in the dermatology department of our hospital between 2001 and 2007. The age of onset ranged from 14 to 26 years. Unusual clinical presentations of pseudomembranous‐like disease were observed in every patient. Causative agents were Microsporum gypseum in five patients and Trichophyton rubrum in one patient. Three of the M. gypseum isolates had atypical morphologies. All six isolates were identified by cultural morphologies and DNA sequence analysis of the internal transcribed spacer region of the ribosomal DNA.

Dynamic time warping assessment of high-resolution melt curves provides a robust metric for fungal identification

Fungal infections are a global problem imposing considerable disease burden. One of the unmet needs in addressing these infections is rapid, sensitive diagnostics. A promising molecular diagnostic approach is high-resolution melt analysis (HRM). However, there has been little effort in leveraging HRM data for automated, objective identification of fungal species. The purpose of these studies was to assess the utility of distance methods developed for comparison of time series data to classify HRM curves as a means of fungal species identification. Dynamic time warping (DTW), first introduced in the context of speech recognition to identify temporal distortion of similar sounds, is an elastic distance measure that has been successfully applied to a wide range of time series data. Comparison of HRM curves of the rDNA internal transcribed spacer (ITS) region from 51 strains of 18 fungal species using DTW distances allowed accurate classification and clustering of all 51 strains. The utility of DTW distances for species identification was demonstrated by matching HRM curves from 243 previously identified clinical isolates against a database of curves from standard reference strains. The results revealed a number of prior misclassifications, discriminated species that are not resolved by routine phenotypic tests, and accurately identified all 243 test strains. In addition to DTW, several other distance functions, Edit Distance on Real sequence (EDR) and Shape-based Distance (SBD), showed promise. It is concluded that DTW-based distances provide a useful metric for the automated identification of fungi based on HRM curves of the ITS region and that this provides the foundation for a robust and automatable method applicable to the clinical setting.

Successful treatment of chromoblastomycosis of 10-year duration due to Fonsecaea nubica

We report a case of chromoblastomycosis due to the presence of large plaque and verrucous hyperplasia lesions on the left upper limb, with elbow abnormal activities, in a 56‐year‐old male. The diagnosis of chromoblastomycosis was based on gross and microscopic morphologies, histopathological examination and clinical manifestation. Molecular tools were applied to identifying the causative agent Fonsecaea nubica, which is rarely reported to be associated with chromoblastomycosis. The patient was initially treated orally with terbinafine (250 mg/day) and itraconazole (200 mg/day), subsequently patient received thermotherapy (45‐50°C, 3 h/day) for 1 month. The patient was successfully cured. A literature review was performed to assess general features, treatment and outcome of chromoblastomycosis due to F. nubica. All the 5 reviewed patients were male, over 30 years old and their lesions occurred after traumatic inoculation.